Push filter with floating key lock

ABSTRACT

A filter assembly for fluid filtration having a push-activated lock and release mechanism. A push filter design activates a floating key lock upon insertion and extraction, where the filter key may be used simultaneously as a lock and as an identifier for particular filter attributes. The filter base may be situated inline, and in fluid communication, with influent and effluent piping, such as within a refrigerator. The filter housing assembly may be attached to, and removed from, the filter base by a push-actuated release. Upon insertion, the filter key shifts the filter lock longitudinally to receive interlocking segments. Upon extraction, the same axial push shifts the filter lock further to align the interlocking fingers within gaps that allow for easy extraction. The specific key lock design allows a user to identify and match certain filter configurations received by the mechanical support, and reject other filter configurations.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention relates to a filtering apparatus, specifically a filterhousing apparatus to facilitate easy removal and replacement of a filterhousing from a mechanical support, and more specifically, to a pushfilter design that activates a floating key lock, where the key may beused simultaneously as a lock and as an identifier for particular filterattributes. The mechanical support may be situated inline, and in fluidcommunication, with influent and effluent piping, such as within arefrigerator. More specifically, the invention relates to a filterhousing and mount, whereby the filter housing may be attached to, andremoved from, the mount by a push-actuated release. A controlledattachment or detachment of the filter sump, containing the filtermedia, is activated by the axial push of the sump towards the mechanicalsupport. The specific key lock design allows a user to identify andmatch certain filter configurations received by the mechanical support,and reject other filter configurations. An internal shutoff, activatedby the push-actuated release, blocks spillage during filter housingremoval and replacement.

2. Description of Related Art

The invention relates to a water filtration system having a locking andunlocking mechanism for changing the filter when the filter media hasserved its useful life. The use of liquid filtration devices is wellknown in the art as shown in U.S. Pat. Nos. 5,135,645, 5,914,037 and6,632,355. Although these patents show filters for water filtration, thefilters are difficult to replace owing to their design and placement.For example, U.S. Pat. No. 5,135,645 discloses a filter cartridge as aplug-in cartridge with a series of switches to prevent the flow of waterwhen the filter cartridge is removed for replacement. The filter must bemanually inserted and removed and have a switch activated to activatevalve mechanisms so as to prevent the flow of water when the filter isremoved. The cover of the filter is placed in the sidewall of arefrigerator and is employed to activate the switches that activate thevalves. The filter access is coplanar with the refrigerator wall andforces an awkward access to the filter cartridge.

In U.S. patent application Ser. No. 11/511,599 filed on Aug. 28, 2006,for Huda, entitled: “FILTER HOUSING APPARATUS WITH ROTATING FILTERREPLACEMENT MECHANISM,” a filter assembly having a rotator actuatingmechanism including a first internal rotator and a second internalrotator is taught as an efficient way to insert, lock, and remove thefilter housing from its base. A simple push mechanism actuates theself-driving release and change over means that hold and release thefilter housing sump, and provide influent shutoff to prevent leaking andspillage. Rotational shutoff and locking mechanisms are activated andreleased by axial force on the filter housing at the commencement of thefilter changing procedure.

The instant invention is particularly useful as the water filteringsystem for a refrigerator having water dispensing means and, optionally,an ice dispensing means. The water used in the refrigerator or water andice may contain contaminants from municipal water sources or fromunderground well or aquifers. Accordingly, it is advantageous to providea water filtration system to remove rust, sand, silt, dirt, sediment,heavy metals, microbiological contaminants, such as Giardia cysts,chlorine, pesticides, mercury, benzene, toluene, MTBE, Cadmium bacteria,viruses, and other know contaminants. Particularly useful water filtermedia for microbiological contaminants include those found in U.S. Pat.Nos. 6,872,311, 6,835,311, 6,797,167, 6,630,016, 5,331,037, and5,147,722, and are incorporated herein by reference thereto. One of theuses of the instant filter apparatus is as a water filtration apparatusfor a refrigerator. Refrigerators are appliances with an outer cabinet,a refrigeration compartment disposed within the outer cabinet and havinga rear wall, a pair of opposing side walls, at least one door disposedopposite the rear wall, a top and a bottom and a freezer compartmentdisposed in the outer cabinet and adjacent to the refrigerationcompartment. It is common for refrigerators to have a water dispenserdisposed in the door and in fluid communication with a source of waterand a filter for filtering the water. Further, it is common forrefrigerators to have an ice dispenser in the door and be in fluidcommunication with a source of water and a filter for filtering thewater. It has been found that the filter assembly of the instantinvention is useful as a filter for a refrigerator having a waterdispenser and/or an ice dispenser.

SUMMARY OF THE INVENTION

The present invention is directed to, in a first aspect, a filterhousing assembly comprising: a filter housing for enclosing a filtermedia, the filter housing having a body and a top portion for forming afluid-tight seal with the body, the filter housing top portionincluding: an ingress port; an egress port; an elongated protrusionextending from a top surface of the filter housing top portion; and afilter key located on the top portion and having a top surface,longitudinal sides, and lateral sides, the filter key including aplurality of spaced protrusions or fingers on each longitudinal side ofthe filter key extending laterally from the top surface, wherein thefingers include winged extensions having slanted or angled faces formating attachment to a filter base or manifold, the filter key having agroove complementary to the elongated protrusion for insertably securingthe filter key to the filter housing top portion by slidably mating theelongated protrusion of the filter housing top portion within the filterkey groove.

The fingers on the filter key may have a diamond shaped cross-section.

The filter key may be attached to the filter housing top portion by snapfit, friction fit, welding, or bonding.

The filter housing top portion is attachable to a filter manifold orbase, the filter manifold or base comprising an attachment structure forfixably receiving the spaced protrusions or fingers on the longitudinalsides of the filter key.

The ingress or egress ports may be integrally formed on the filterhousing top portion. The ingress port and the egress port are off axialcenter of the filter housing. The filter housing top portion may be aone-piece construction or multiple components integrally attached andsecured.

The spaced protrusions or fingers are integrally formed with the filterkey.

The filter housing body may include at least one strengthening rib,which may also be used as a guide for correct alignment during insertionwithin the filter base.

The at least one strengthening rib preferably protrudes radially fromthe filter housing body and extends longitudinally intermediate betweentop and bottom portions of the filter housing.

The filter key may also include an indented angled ramp segment on atleast one bottom edge, and the filter housing top portion includes atleast one protruding angled ramp segment for complementary mating withthe angled ramp segment on the filter key.

In a second aspect, the present invention is directed to a filterhousing assembly comprising: a filter housing for enclosing a filtermedia; a filter head having two ports for ingress and egress integralwith the filter head and in fluid communication with the filter media,the filter head forming a fluid-tight seal with the filter housing and afirst attachment structure located on the filter head for receiving afilter key; and the filter key having a top surface, a bottom,longitudinal sides, and lateral sides, the filter key including: aplurality of spaced protrusions or fingers on each longitudinal side ofthe filter key extending laterally from the top surface and havingwinged extensions; and a second attachment structure located on thefilter key bottom for attaching the filter key to the first attachmentstructure on the filter manifold.

In a third aspect, the present invention is directed to a filter basefor releasably connecting to a complementary mating filter housingassembly comprising: a base platform having fluid ingress and egressports; and a floating lock in sliding communication with the baseplatform, having a bottom surface, a top surface, and longitudinal andlateral sides, the floating lock including: spaced protrusions, drivekeys, or fingers on the longitudinal sides extending laterally inwards,including at least one shaped protrusion, finger, or drive key forslidably contacting the complementary mating filter housing assembly,the at least one shaped protrusion, finger, or drive key including anangled face exposed towards the bottom surface.

The floating lock may include a position stop centered about the lateralsides, and located above the at least one drive key to provide aphysical stop during insertion of the complementary mating filter key.The filter key includes a track structure longitudinally across thefloating lock. The filter base includes an enclosure for receiving thefloating lock, the enclosure allowing the floating lock to slidably movetherein.

In a fourth aspect, the present invention is directed to a filter basein combination with a filter housing assembly, the combinationcomprising: a filter base having an ingress port and an egress port on abase platform; a slidable floating lock in slidable contact of thefilter base, the floating lock having a plurality of drive keys orlateral extensions separated by gaps; a resilient member in contact withthe floating lock, providing a retraction force for the floating lock; afilter housing assembly including a top portion having a filter headwith a top surface, a first attachment structure and an elongatedprotrusion extending from the filter head top surface, and at least oneprotruding angled ramp segment for complementary mating with the angledramp segment on the filter key; and a filter key located on a topportion of the filter housing assembly, the filter key havinglongitudinal sides and lateral sides, the filter key including: aplurality of spaced protrusions or fingers on each longitudinal side ofthe filter key extending laterally from the top surface, wherein thefingers include winged extensions having slanted or angled faces formating attachment to a filter base or manifold; a second attachmentstructure having a groove complementary to the elongated protrusion forinsertably securing the filter key to the filter head top surface byslidably mating the elongated protrusion of the filter head within thegroove; and an indented angled ramp segment on at least one bottom edge.

The floating lock may include: a bottom surface, a top surface, andlongitudinal and lateral sides, and wherein the lateral extensionsinclude drive keys on the longitudinal sides extending laterally inwardsat the bottom surface for slidably receiving the filter key, each of thedrive keys including an angled portion exposed towards the bottomsurface, and an edge or wedge on each of the drive key bottom forreleasably contacting with a portion of the filter key; and a positionkey centered about the floating lock, and located above the drive keysto provide a physical stop during insertion of the filter housingassembly.

The filter head includes a top surface with a first attachment structureand an elongated protrusion extending from the filter head top surface,and the filter key includes a second attachment structure having agroove complementary to the elongated protrusion for insertably securingthe filter key to the filter head top surface by slidably mating theelongated protrusion of the filter head within the groove.

It is an object of this invention to provide a filter housing apparatusmounted to a base and having an automatic locking mechanism for simplereplacement and removal.

It is an object of this invention to provide a filter housing apparatusand base attached by a push activated, slideably moveable, floatinglock.

It is another object of this invention to provide a filter housingapparatus mounted on a surface having non-rotating locking means withpressure activation for replacement and removal.

It is another object of the present invention to provide a filterhousing apparatus that allows for a keyed identification of the filter.

It is a further object of this invention to provide a filter housingapparatus for use with water dispensing and\or ice dispensing apparatuswhereby filtered water is provided to the water dispensing and/or icedispensing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention believed to be novel and the elementscharacteristic of the invention are set forth with particularity in theappended claims. The figures are for illustration purposes only and arenot drawn to scale. The invention itself, however, both as toorganization and method of operation, may best be understood byreference to the description of the preferred embodiment(s), whichfollows, taken in conjunction with the accompanying drawings in which:

FIG. 1A is a top exploded view of one embodiment of the filter assemblyof the present invention.

FIG. 1B is a side plan view the embodiment of the filter housingassembly of FIG. 1A.

FIG. 1C depicts a perspective view of the filter housing assembly withstrengthening ribs extending at least partially down the outer surfaceof the filter housing.

FIG. 2A is a perspective view of one embodiment of the filter key of thepresent invention.

FIG. 2B is a lateral side view of the filter key of FIG. 2A.

FIG. 2C depicts a bottom plan view of the filter key of FIG. 2A showinga groove and a locking nub or tab for attachments.

FIG. 2D depicts a perspective view from the opposite side of the filterkey of FIG. 2C.

FIG. 2E depicts a bottom view of the filter key of FIG. 2A.

FIG. 2F is a longitudinal side view of the filter key of FIG. 2A.

FIG. 2G depicts a slotted groove which includes a wider upper portionfor securely affixing the filter key to the filter head or filtermanifold.

FIG. 2H is a side view of the filter key depicting an angled, rampsegment, which at least partially extends the length of the bottomsurface of the filter key.

FIG. 2I depicts the complementary angled ramp segment for the filter keyof FIG. 2I-1.

FIG. 2J depicts a side view of a partial section of the filter headshowing a mating protrusion for interlocking with the slotted groove onthe filter key, and complementary angled ramp segments for interlockingwith the ramp segments on the filter key bottom edges.

FIG. 3A depicts a perspective view of one embodiment of the floatinglock or sliding lock of the present invention.

FIG. 3B is a perspective view from the opposite side of the floatinglock of FIG. 3A.

FIG. 3C is a lateral side view of the floating lock of FIG. 3A.

FIG. 3D depicts a top view of the floating lock of FIG. 3A.

FIG. 3E depicts cross-sectional longitudinal side view of the floatinglock of FIG. 3A.

FIG. 4A is a perspective view of one embodiment of the filter manifold.

FIG. 4B is a top plan view of a second embodiment of the filter manifoldwith an extension support member.

FIG. 4C is a perspective view of a second embodiment of the filtermanifold.

FIG. 5A is a side view of one embodiment of the filter head of thepresent invention.

FIG. 5B is a bottom perspective view of the filter head of FIG. 5A.

FIG. 5C is a top perspective view of the filter head of FIG. 5A.

FIG. 5D is another embodiment of the filter head with a snap fit lockfor the filter key.

FIG. 5E is a bottom perspective view of the filter head of FIG. 5D.

FIG. 5F is a top perspective view of the filter head depicting theaperture for receiving the filter key.

FIG. 5G depicts a one-piece or integrated filter head/filter manifoldconstruction having ingress and egress ports for fluid flow.

FIG. 5H is a side view of the integrated, one-piece filter head of FIG.5G.

FIG. 5I is a bottom view of the integrated, one-piece filter head ofFIG. 5G, depicting an off axial center cylinder for receiving an end capport of the filter cartridge.

FIGS. 6A and 6B are exploded views of a second embodiment of the filterassembly of the present invention, showing a filter key having anextended boss.

FIG. 7A is a top perspective view of an embodiment of the filter key ofthe present invention having an extended boss.

FIG. 7B is a bottom perspective view of the filter key of FIG. 7A.

FIG. 7C depicts a top plan view of the filter key of FIG. 7A.

FIG. 7D depicts a side plan view of the filter key of FIG. 7A.

FIG. 7E depicts an end or lateral side view of the embodiment of thefilter key of FIG. 7A, showing the boss rising above the plane createdby the fingers, and two wings extending laterally outwards from theboss.

FIG. 7F is a perspective view of another embodiment of the filter key ofthe present invention showing a locking nub located on the bottomportion on a lateral side.

FIG. 8A depicts a perspective view of an embodiment of the floating lockof the present invention.

FIG. 8B is a top view of the floating lock of FIG. 8A.

FIG. 8C is a cross-sectional view of the floating lock of FIG. 8Adepicting a drive key located at one end of the floating lock on thelongitudinal or side panel.

FIG. 8D depicts an exploded view of the drive key of FIG. 8C showing theedge angle and face.

FIG. 8E depicts a perspective view of a floating lock having anextension member.

FIG. 8F is a side view of the floating lock of FIG. 8E having anextension member.

FIG. 8G is a lateral or cross-sectional view of the floating lock ofFIG. 8E with an extension member.

FIG. 9A is a perspective view of a non-floating port of the presentinvention.

FIG. 9B is a top plan view of the non-floating port of FIG. 9A.

FIG. 10A is a top plan view of one embodiment of the rear plate of thepresent invention.

FIG. 10B is a bottom perspective view of the rear plate of FIG. 10A.

FIG. 10C is a top plan view of a second embodiment of the rear plate ofthe present invention.

FIG. 11 is an exploded view of a filter assembly of the presentinvention, showing a filter key having a boss, connected to a filtermanifold having extension supports.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

In describing the preferred embodiment of the present invention,reference will be made herein to FIGS. 1 to 11 of the drawings in whichlike numerals refer to like features of the invention. Features of theinvention are not necessarily shown to scale.

The present invention is directed to a filter housing assembly forfiltration of liquids, including the interception of chemical,particulate, and/or microbiological contaminants. The use of themechanical locking assembly of the filter housing without the need forexcess force and tight tolerances essential in prior art filter housingsmakes for easy and frequent filter changes and optimal filterperformance. The filter housing assembly of the present inventionprovides simplified filter changes to minimize process downtime andwithout recourse to tools. A simple push mechanism actuates theself-driving release and change over means that hold and release thefilter housing sump or filter cartridge, and provides influent shutoffmeans to prevent leaking and spillage. A floating lock or sliding lockresponsive to an axial insertion force from the filter cartridge movesperpendicular or radially to the axial motion of the sump, and allows aspecific connector piece or filter key to insert within the floatinglock. Once inserted, the floating lock retracts towards its originalposition under a resilient force, such as two springs in tandem, orother complementary resilient mechanism keeping the floating lock underretraction tension when moved from its initial position. The filter keyand floating lock combination allows for the identification of specificfilter models and may be configured to reject all but specific filtertypes.

Removal of the filter cartridge is performed in the same manner. Anaxial insertion force causes the floating lock to move radially, whichallows the filter key to be removed from the floating lock. Anextraction force provided by spring tension, or the like, helps push thefilter cartridge out of its base. Fluid shutoff and locking mechanismsare initiated by the axial force on the filter cartridge at thecommencement of the filter changing procedure.

The present invention is described below in reference to its applicationin connection with, and operation of, a water treatment system. However,it should be apparent to those having ordinary skill in the art that theinvention may be applicable to any device having a need for filteringliquid.

FIG. 1A is a top exploded view of the preferred embodiment of the filterassembly of the present invention. The filter assembly is fixablysecured in a position within an operating environment requiring fluidfiltration, such as attached to an internal sidewall of a refrigerator,although certainly other operating environments may be envisioned, andthe filter assembly may be used in any number of environments where thefilter assembly has access to, and can be placed in fluid communicationwith, influent and effluent fluid access ports. For illustrativepurposes only, application to the filtering of water being piped into arefrigerator is discussed.

A filter housing assembly 200 comprises the removable, detachable filtercartridge or sump of the filter assembly from a filter base 100. Filterhousing assembly 200 includes a filter housing 1, which encloses filtermedia 8, a filter head 2 that attaches at one end to filter housing 1,and attaches at the other end to a filter manifold 3 and non-floatingport 11. A connector piece or filter key 5 is attached to filtermanifold 3. Filter base 100 includes non-floating port 11, floating lock12, and rear plate 13. Filter head 2 secures in a water-tight fit tofilter housing 1. The attachment scheme may be made by a water-tightscrew fit, bond, weld, or other water-tight fastening mechanism commonlyused in the art for sealing adjoining components, typically adjoiningplastic components. As discussed in further detail below, filter key 5is connected to filter manifold 3. Filter key 5 may be formed as onepiece with filter manifold 3, or may be securely attached by othermethods, such as bonding, welding, press fit, friction fit, or the like.Filter key 5 may also be removably attached for replacement by an enduser. Filter manifold 3 is attached to filter head 2. Filter media 8 islocated in filter housing 1. Each end of filter media 8 is secured by acap that facilitates the direction of the fluid being treated by thefilter. At one end, filter media 8 is secured by a closed end cap 7, andat the other end by open end cap 6. Filter media 8 may be any filtermedia known in the art, and preferably, is a carbon block filter. It istypically shaped in a similar fashion as filter housing 1, which in thepreferred embodiment is cylindrical. Open end cap 6 is designed tointerface and be in fluid communication with filter head 2.

In another embodiment, filter housing 1 may include strengthening ribs16 longitudinally located on the filter housing outer surface. FIG. 1Cdepicts a perspective view of filter housing assembly 200 with a row ofstrengthening ribs extending at least partially down the outer surfaceof filter housing 1. Strengthening ribs 16 also function as a guide forinserting filter housing assembly 200 into a shroud (not shown) that maybe part of the installation assembly for ensuring proper alignment withfilter base 100. Strengthening ribs 16 is preferably integral withfilter housing 1, but may also be attachable as a separate componentpart. Ribs 16 may extend the full length of filter housing 1, or asshown, may extend to an intermediate point between filter housingassembly 200 end caps 6, 7.

Filter housing assembly 200 is a finished assembly including filterhousing 1, which encompasses filter media 8 by closed end cap 7 at oneend, and open end cap 6 at the other. Generally, o-ring seals, such aso-ring seal 9, are used to prevent water leakage where differentcomponents are expected to mate. Filter manifold 3 and filter key 5 arejoined with filter head 2, and secured to filter housing 1 to form theassembled filter housing apparatus 200. These components may beintegral, permanently secured, or removably attached to one another, andto filter head 2. FIG. 1B is a side plan view of the preferredembodiment of the filter assembly of the present invention.

FIG. 2A is a perspective view of connector piece or filter key 5.

FIG. 2B is a lateral side view of filter key 5. As previously noted, thebottom of filter key 5 is attached to filter manifold 3 by any number offastening schemes, or may be integrally formed with filter manifold 3.

FIG. 2C depicts a groove 51 that is preferably shaped to receive acomplementary protrusion on filter manifold 3, and is preferably shapedto receive a dovetail protrusion; however, other connecting,complementary shapes are not excluded.

For example, FIG. 2G depicts a slotted groove 51 b that is not adovetail joint. Slotted groove 51 b may include a wider upper portion 51c to more securely affix filter key 5 to filter manifold 3. Theconnection of filter key 5 with filter manifold 3 may be bonded, sonicwelded, press fitted, friction fitted, or the like. Moreover, filter key5 may be integral with filter manifold 3. Similarly, filter manifold 3may be bonded, sonic welded, press fitted, friction fitted, or integralwith the filter housing top portion. As depicted in the illustrativeembodiment, groove 51 is shaped to accept a snap feature for a press orsnap fit located on filter manifold 3. In this manner filter key 5 maybe removably attached to filter manifold 3. Similarly, filter manifold 3may be designed to be removably attached to filter head 2. Thus, thedesign has more flexibility to introduce and accommodate different keyconfigurations, which can be used to designate specific filter types,and purposely reject other filter types. Additionally, filter key 5 mayinclude an angled, ramp segment 59 a on at least its bottom edges wherefilter key 5 slidably mates with the top surface of filter manifold 3 orfilter head 400.

FIG. 2H is a side view of filter key 5 depicting angled ramp segment 59a, which at least partially extends the length of the bottom surface offilter key 5. Angled ramp 59 a is located at one end of the bottom edgesof filter key 5 and extends into the filter key main body 5 a.

FIG. 2I depicts a perspective view of filter head 400 with complementaryangled ramp segments 59 b for mating with angled ramp segments 59 a offilter key 5. Angled ramp segment 59 a matably adjoins complementaryangled ramp segment 59 b to interlock and assist in securing filter key5 to filter head 400. For the two piece design utilizing filter manifold3, complementary angled ramp segments 59 b are formed on the top surfaceof filter manifold 3.

FIG. 2J depicts a side view of a partial section of filter head 400showing mating protrusion or rail 321 for interlocking with slottedgroove 51 b, and complementary angled ramp segments 59 b.

FIG. 4A depicts a perspective view of the one embodiment of filtermanifold 300. Port 310 is shown off center of filter manifold 300. FIG.4A depicts the filter manifold without extension support members.Preferably, port 310 is an outlet port; however, the present inventionis not limited to a specific ingress and egress location, and may havethese ports interchanged. When port 310 is used as an egress or outletport, filter manifold 300 takes fluid from filter media 8 through thecenter port of open cap 6, and directs fluid flow radially outwards fromthe axial center to port 310. In this embodiment, the ingress port islocated on filter head 2. By locating the ingress and egress ports offaxis, filter housing assembly 200 has a more robust design, withenhanced structural integrity for mounting to the filter base, and forremaining fixably in place during attachment.

Referring to FIGS. 4A-4C, in a preferred attachment scheme for filterkey 5, a protrusion or rail 32 or 320 is formed on or near the centerline of filter manifold 3 or 300. Protrusion or rail 32 or 320 ispreferably a rectangular shaped segment extending above circular centerportion 33 or 330. Protrusion or rail 32 allows for precise alignment offilter key 5, while providing a robust connection. Preferably, adovetail shape, press fit, or friction fit interconnection betweenprotrusion 32 and groove 51 of filter key 5 permits the user to removeand replace filter key 5. This allows for the designation of specificfilter keys, and correspondingly, specific filter cartridges. Protrusionor rail 32, 320 may be integrally formed with filter manifold 3 or 300,respectively, and filter manifold 3 may be integrally formed with thefilter housing top portion. Or these components may be separatelyfabricated and attached by bond, weld, press fit, friction fit, or othersuitable means known in the art. Preferably, protrusion or rail 32, 320has a dovetail shaped surface for slidably mating with complementarygroove 51 of filter key 5.

In the embodiment depicted by FIGS. 4B and 4C, protrusion 32 may be onan extension support 34. FIG. 4B depicts a top level view of filtermanifold 3, showing extension support 34 extending longitudinally orradially outward from center portion 33, along a radius. Extensionsupport 34 supports optional shroud 4 that covers and protects filterhead 2. Filter manifold 3 or 300 seats within and attaches to filterhead 2.

FIG. 5A depicts a side view of one embodiment of filter head 2. Filterhead 2 is shown with off-center port 21. In this manner, port 21 offilter head 2 and port 31 of filter manifold 3 are both off-center andparallel to one another about a plane that approximately intersects thecenter point of filter head 2. As shown in FIGS. 1, 4, and 5, a recessedportion 22 formed about the center point of filter head 2 receivescenter portion 33 of filter manifold 3. If extension support 34 is usedwith filter manifold 3, when filter manifold 3 is inserted within filterhead 2, extension support 34 is situated approximately perpendicular tothe plane formed by ports 21 and 31. Extension support 34 provides ateach end a snap fit design for shroud 4.

FIG. 5B is a bottom perspective view of the filter head.

FIG. 5C is a top perspective view of filter head 2 depicting recessportion 22.

Filter head 210 depicts another embodiment as shown in FIGS. 5D-5F. Inthis embodiment, as depicted in the top perspective view of FIG. 5F, onthe top surface of filter head 210 is a curved receiving boss or supportmember 230 located on one side of the center point, and two parallel,lateral support members 240 a,b located opposite curved boss 230 on theother side of the center point of filter head 210. These structuralsupport members are used to align filter key 5 to filter head 210, andhelp secure filter key 5. This filter head may be used in conjunctionwith the filter manifold 300 without extension supports, as depicted inFIG. 4A. Structural support member 230 provides a physical stop forfilter key 5, which typically slides on protrusion 32 provided by filtermanifold 300. Lateral support members 240 a,b are used to align filterkey 5, and prevent it from inadvertent shifting. FIG. 5E is a bottomperspective view of filter head 210. FIG. 5D is a side view of filterhead 210.

In another embodiment, filter head 2, 210 may be integral with filtermanifold 3, 310, such as for example, a one piece construction in theform of a single injected molded piece, or a two piece construction withfilter manifold 3, 310 welded, fused, or otherwise permanently attachedto filter head 2, 210 as a subassembly.

FIG. 5G depicts a one-piece or integrated filter head/filter manifoldconstruction 400 having ingress and egress ports 410 a,b. Protrusion 420is preferably a shaped segment extending above, and off axis from, thecircular center of filter head 400. Protrusion 420 allows for precisealignment of filter key 5, while providing a robust connection. Adovetail shape, press fit, or friction fit interconnection betweenprotrusion 420 and groove 51 of filter key 5 permits the user to removeand replace filter key 5. FIG.

5H is a side view of integrated, one-piece filter head 400. Cylindricalwall 424 is sized to receive the open end cap 6 of filter housing 1.Cylindrical wall 426 is off the axial center of filter head 400 and isconfigured to receive the center axial port of end cap 6, redirectingfluid flow off the axial center such that port 410 b is within cylinder426, and port 410 a is outside of cylinder 426. This redirection offluid flow performs a similar function as filter manifold 3, 310 withoutthe need of aligning the center axial port of end cap 6 with a filtermanifold aperture.

FIG. 5I is a bottom view of the integrated, one-piece filter head ofFIG. 5G, depicting off axial center cylinder 426 for receiving a port ofopen end cap 6 of the filter cartridge. A comparison to FIGS. 5B and 5Ewhich depict perspective views of the underside of filter head 2, 210respectively, with FIG. 5I, demonstrates the absence of an axiallycentered cylinder for receiving the port from open end cap 6 in theintegrated filter head 400 design.

Filter manifold 300 includes an off-center port 310, as well as a centerportion 330 that fits securely within recess 220 of filter head 210.Protrusion 320 receives the groove from filter key 5. In thisembodiment, when filter key 5 is slidably inserted within protrusion320, structural support member 230 and lateral structural supportmembers 240 a,b secure filter key 5. The curved portion of structuralsupport member 230 forces filter key 5 to be inserted in one directiononly. An added boss 232, located on the top of filter head 210 andcentered between lateral support members 240 a,b may be employed toserve as a lock or snap fit for filter key 5. Additionally, in anotherembodiment, structural support member 230 may be formed with a smallaperture 235 located directly away from the center point of filter head210 at its base where support member 230 meets the top portion of filterhead 210. This small aperture 235 is designed to receive a protrudingmaterial or locking nub or tab 53 placed at, or formed with, thecorresponding end portion of filter key 5 on the lower end of a lateralside. Locking nub or tab 53 on filter key 5 is inserted within smallaperture 235 on the curved portion of structural support member 230 andprevents axial removal of filter key 5 away from filter head 210. FIGS.2A-2F show locking nub 53 located on the bottom portion of a lateralside of filter key 5. FIG. 5D is a side view of filter head 210depicting aperture 235 for receiving filter key 5.

Filter key 5 includes at least one laterally extending finger 52, andpreferably a plurality of extending fingers, as depicted in FIGS. 2A-2F.FIG. 2C is a bottom perspective view of filter key 5. In a firstillustrative embodiment, filter key 5 is shown with ten laterallyextending fingers 52. Fingers 52 are preferably constructed of the samematerial as, and integrally formed with, base 55 of filter key 5.However, the fingers may also be removably attached, and the filter keydesign is not limited to an integrally formed construction. Thelaterally extending fingers 52 may form a number of differentconfigurations. In the illustrative embodiment, there is a uniform gap54 between each finger 52. In other configurations, a finger may bemissing on one or both sides of filter key 5, and gap 54 may be wider insome places than in others. Using a digital 1, 0 designations toindicate a finger (1) or a gap (0), it is possible to have manydifferent configurations for a filter key. The configuration as shown inFIG. 2E would be designated on each side as 101010101. As a separateexample, for a designation of 100010101, this would represent a lateralfinger (1) followed by a wide gap (000), and then a finger (1) followedby a gap (0) and a finger (1) followed by another gap (0), and one lastfinger (1). The present invention is not limited to any particularfinger/gap order. Additionally, it is not necessary for the finger/gapconfiguration on one side of filter key 5 to be symmetric with thefinger/gap configuration on the opposite side. By having differentfinger/gap configurations, it is possible to make a mechanical keyidentifier for the specific filter housing assembly being employed.Filter key 5 may also be color-coded to facilitate identification fordifferent filter cartridges or housing assemblies. It may also betextured, mirrored, transparent, translucent, materially modified, orhaving a conductively signature, or any combination thereof, foridentification purposes. More importantly, aside from identification ofthe filter housing assembly, a particular filter key finger/gapconfiguration will only allow for the use of a specific filter housingassembly in a given system.

Fingers 52 of filter key 5 are strength bearing members, used to matewith, or interlock with, corresponding drive keys 123 a,b located onlongitudinal sides of floating lock 12 as depicted in FIG. 3. There mustbe at least one drive key on floating lock 12 that corresponds to, andlines up with, at least one finger on filter key 5, so that when filterkey 5 is inserted to mate with floating lock 12, the drive keys slidablycontact the fingers and floating lock 12 is shifted longitudinally anincremental amount to allow fingers 52 on filter key 5 to traversebetween the gaps 122 on floating lock 12. Once fingers 52 have passedbetween the corresponding gaps on floating lock 12, which is slidablyrestrained under tensional forces, floating lock 12 is partiallyreturned towards its original position by the tensional retractionforces so that at least one finger on filter key 5 aligns or interlockswith at least one drive key on floating lock 12, and the alignmentresists any direct outward, axial extraction forces.

Each finger 52 of filter key 5 includes a slanted face 58 as depicted inFIGS. 2A and 2F. These angled features are made to slidably contactcomplementary slanted edge or angled features 121 a,b of drive keys 123a,b of floating lock 12 shown in FIGS. 3A and 3E. During insertion offilter key 5, the sliding contact of the angled feature of the filterkey's fingers transversely shifts floating lock 12 off of its initialposition, and allows the fingers of filter key 5 to be inserted withingaps 122 between the drive keys 123 a,b.

A perspective view of floating lock 12 is depicted in FIGS. 3A and 3B.Floating lock 12 has angled-faced fingers, protrusions, or drive keys123 a,b and gaps 122 that may reciprocally correspond to fingers 52 andgaps 54 located on filter key 5. It is not necessary for the drivekey/gap configuration of floating lock 12 to be exactly complementary tothe finger/gap configuration of filter key 5. It is only necessary thatfloating lock 12 is able to fully receive the inserting filter key 5when filter housing assembly 200 is axially inserted into filter base100. Each drive key 123 a,b of floating lock 12 is shaped with areceiving wedge 129 a,b, respectively, opposite slanted edge 121 a,b tocapture fingers 52 of filter key 5. Fingers 52 may have across-sectional diamond shape to facilitate the capture by the drive keyreceiving wedge 129 a,b. Drive keys 123 a,b are placed on at least onelongitudinal side of floating lock 12, as depicted in FIGS. 3D and 3E.Underneath and centered between drive keys 123 a,b is a row of positionstops 125. Position stops 125 preclude fingers 52 from extending anyfurther during insertion. There need not be a position stop 125 for eachdrive key 123 a,b, provided there is at least one position stop 125 toprohibit over insertion of filter key 5. Position stops 125 also includea slanted or angled face 126 for slidable contact with slanted face 58of fingers 52 on filter key 5. Position stops 125 are shown as a row ofjagged edges, but do not have to correspond one-for-one with drive keys123 a,b.

Upon insertion, when fingers 52 of filter key 5 contact drive keys 123a,b, floating lock 12 shifts away from its initial position, againstretraction forces, and moves according to the contacting angled edges 58and 121. Once wings 56 a,b of fingers 52 clear lip 127 a,b of drive keys123 a,b, floating lock 12 is not prohibited from reacting to theretraction forces, and moves slightly back, towards its originalposition where diamond shaped wings 56 a,b are then trapped by receivingwedges 129 a,b. This position locks filter key 5 to floating lock 12resisting any a direct axial extraction force.

There is a gap or space 124 between the bottom most portion of drive key123 a,b and top most portion of position stop 125. Upon extraction, whenwings 56 a,b of fingers 52 are pushed within this gap or space, there isno structure preventing floating lock 12 from responding to thetensional retraction forces acting on it. Thus, floating lock 12 is freeto respond to the retraction forces, and will tend to move towards itsinitial position. This will align fingers 52 of filter key 5 within gaps122 of floating lock 12 and allow for easy extraction of filter housing200.

In order to extract filter housing assembly 200, a user again pushesaxially inwards on the filter housing assembly, which releases wings 56a,b on filter key 5 from drive keys 123 a,b. This frees floating lock 12to return to towards its original position, and locates fingers 52 onfilter key 5 at gaps 122 of floating lock 12. Filter housing assembly200 can now be freely extracted from filter base 100. Resilient members1110 within shut-off stanchions 1101 a,b of non-floating port 11 assistin pushing or extracting filter housing assembly 200 away from filterbase 100.

FIG. 9A is a perspective view of non-floating port 11, which works intandem with rear plate 13 or rear plate 1300 to hold floating or slidinglock 12 in place while allowing it to freely move longitudinally off itscenter position and back to its center position during the insertion andextraction of filter housing assembly 200. As discussed further herein,non-floating port 11 will also hold floating lock 1200 and floating lock1212 of FIG. 8. For simplicity, reference is made chiefly to theinteraction of non-floating port 11 with floating lock 12, although theapplicability of non-floating port 11 includes usage with floating lock1200 and 1212 as well. Non-floating port 11 includes a protrudingencasement 1102, larger than floating lock 12, and made to enclosefloating lock 12 therein. Encasement 1102 prevents over-travel offloating lock 12, and protects it when installed from extraneous,unintended movement.

FIG. 9B is a top plan view of non-floating port 11. Stanchions 1101 a,bare located on opposite sides of encasement 1102. Ports 1103 representthe ingress and egress ports for the fluid. Shut-off stanchions 1101 a,binclude shutoff plugs 14, which act as valve seals to stop fluid flowwhen the filter cartridge is being removed. Shut-off stanchions 1101 a,bare preferably cylindrical in shape, containing spring activated, o-ringsealed plugs for sealing the ingress and egress lines during filtercartridge removal. In a preferred embodiment, rear plate 13 is snapfitted into non-floating port 11. In order to accommodate this, snapfittings 1105 are shown on non-floating port 11 that receive acorresponding fitting 135 on rear plate 13. Referring to FIG. 1,floating lock 12 is supported by non-floating port 11 and rear plate 13.

FIG. 10A is a top plan view of one embodiment of rear plate 13 of thepresent invention.

FIG. 10B depicts a bottom perspective view of rear plate 13. Rear plate13 secures floating lock 12 within a support structure in non-floatingport 11. Rear plate 13 is preferably attached by snap fit tonon-floating port 11, although other attachment schemes known in the artmay be easily employed, such as bonding, welding, and assortedmechanical fasteners. Rear plate 13 is formed with extensions 132 oneach end, and shaped gaps 133 therebetween. Gaps 133 are shaped to goaround shut-off stanchions 1101 a,b of non-floating port 11. In thisembodiment, rear plate 13 includes a center aperture 131 that allows forlongitudinal movement of floating lock 12. Floating lock 12 may includean extension member opposite the face configured with fingers and gaps,in order to permit resilient components, such as helical or torsionsprings to act upon it. FIGS. 3C and 3E are side views of the floatinglock showing extension member 128. FIG. 3B is a perspective view of thefloating lock 12 with extension member 128. FIG. 8E depicts floatinglock 1212 with extension member 1280. In these embodiments, theextension member is acted upon by resilient devices held by the rearplate.

FIG. 10C is a top plan view of another embodiment of the rear plate 1300of the present invention. In this embodiment, the topside of rear plate1300 includes a domed, slotted cover 1302 over the center aperture.Cover 1302 is formed to encase springs or other resilient members aboutthe extension member 128 extending from floating lock 12. Dome 1302includes a slot 1304 that is made to receive the extension member 128from floating lock 12. Slot 1304 helps retain linear movement offloating lock 12 inside dome 1302. In this embodiment, two complementaryresilient members, such as springs, would reside on each side of theextension member 128 of floating lock 12. One resilient memberpreferably applies force on the floating lock extension member in onedirection, while the other resilient member applies force to thefloating lock extension member in the opposite direction. In thismanner, no matter which way floating lock 12 is moved or shifted, aretraction force presents itself to return floating lock 12 to itsoriginal, centered position.

At all times during insertion, the filter housing assembly is underextraction forces that tend to push the housing out of the filter base.These extraction forces result from resilient members in each shut-offstanchion 1101 a,b of non-floating port 11 (shown in FIG. 9B) that forceshutoff plugs 14 into position in order to block the ingress and egressports. Preferably, the extraction forces on shutoff plugs 14 areprovided by a spring 1110 in each port, although other resilient membersmay be used to provide a similar result. Inserting the filter housingassembly into the filter base works against these extraction forces, andpushes shutoff plugs 14 further up each shut-off stanchion 1101 a,b ofnon-floating port 11. This allows for fluid ingress, while keeping thefilter housing assembly under the constant extraction force.

Protective port shroud 4 may be placed over filter head 2, to protectthe floating lock 12 and filter key 5 mechanism from damage and debris.Shroud 4 is preferably supported by the extension supports on the filtermanifold.

FIGS. 6A and 6B are exploded views of another embodiment of the filterassembly of the present invention, showing the combination of filtermanifold 300, filter key 500, and filter head 210. Filter key 500 isdepicted without a locking nub or tab; however it may include a lockingnub to facilitate attachment to the filter head. FIG. 7F depicts filterkey 590 with locking nub or tab 501. Locking nub 501 is located at thebase of filter key 590. In this embodiment, filter key 500 or 590 andfilter manifold 300 are modified such that floating lock 1200 or 1212 ofFIG. 8 is slidably shifted by the interaction wings 560 a,b of anextended boss 550 on filter key 500 or 590 with drive keys 1210 a,b offloating lock 1200.

Filter key 500 or 590 is inserted within floating lock 1200 through theaxial insertion of the filter housing assembly into the filter base.Hammerhead shaped wings 560 a,b on fingers 520 of filter key 500 anddrive keys 1210 a,b on floating lock 1200 or 1212 slidably contact oneanother, causing a transverse motion of floating lock 1200 or 1212perpendicular to the axial motion of insertion. In this manner, floatinglock 1200 or 1212 is shifted longitudinally, in a direction radiallyrelative to the filter housing assembly axis. Fingers 520 of filter key500 are positioned within the gaps 1220 on floating lock 1200 or 1212.Once filter key 500 or 590 is inserted, floating lock 1200 or 1212 isreturned partially towards its original position by retracting tensionalforces, preferably by complementary spring forces, so that the fingerson floating lock 1200 or 1212 align directly with fingers 520 on filterkey 500 or 590, thus preventing a direct extraction force from removingthe filter housing assembly from the filter base.

FIG. 7F depicts a top perspective view of filter key 590. At one end offilter key 590 is an upwardly extended angled boss 550. Boss 550 risesabove horizontal plane 570 created by the top portion of fingers 520,and is angled toward fingers 520, with its highest point at one end offilter key 500. Boss 550 angles downward from its highest point towardsfingers 520. Preferably, boss 550 is an upwardly facing triangular orwedge shaped design having wings 560 a,b for interaction with drive keys1210 a,b, respectively, on floating lock 1200.

FIG. 7E depicts an end view of filter key 500 showing a hammerheadshaped boss 550 rising above plane 570 created by fingers 520, and wings560 a,b extending laterally from boss 550 resembling what may beconsidered a hammerhead shape. The purpose of wings 560 a,b is tocontact corresponding angled drive keys 1210 a,b on floating key 1200.

A perspective view of the complementary floating lock 1200 is depictedin FIG. 8A. The only difference between floating lock 1200 of FIG. 8Aand floating lock 1212 of FIG. 8E is the addition of an extension member1280 on floating lock 1212. Floating lock 1200 has fingers 1230 a,b andgaps 1220 that may reciprocally correspond to fingers 520 and gaps 540located on filter key 500 or 590. It is not necessary for the finger/gapconfiguration of floating lock 1200 to be exactly complementary to thefinger/gap configuration of filter key 500 or 590. It is only necessarythat floating lock 1200 is able to fully receive the inserting filterkey 500 when the filter housing assembly is axially inserted into thefilter base. Furthermore, once floating lock 1200 is subjected toretraction forces acting to return it partially towards its originalposition, it is necessary that at least one finger on filter key 500 or590 vertically align with at least one finger on floating lock 1200 or1212 preventing any extraction without further shifting of floating lock1200 or 1212.

Using floating lock 1200 and filter key 500 as illustrative examples,upon slidable contact of wings 560 a,b on filter key 500 and drive keys1210 a,b on floating lock 1200, floating lock 1200 moves in a transversemotion, perpendicular to the axial motion of insertion. In this manner,floating lock 1200 is shifted longitudinally, in a direction radiallyrelative to the filter housing assembly axis. Fingers 520 of filter key500 are positioned within the gaps 1220 on floating lock 1200. Oncefilter key 500 is inserted, floating lock 1200 is returned partiallytowards its original position by retracting tensional forces, preferablyby complementary spring forces, so that the fingers on floating lock1200 align directly with fingers 520 on filter key 500, thus preventinga direct extraction force from removing the filter housing assembly fromthe filter base.

Fingers 1230 a,b are preferably constructed of the same material asfloating lock 1200 and integrally formed therewith. However, fingers1230 may also be removably attached, and the floating lock design is notlimited to an integrally formed construction. Additionally, the presentinvention is not limited to any particular finger/gap order. It is notnecessary for the finger/gap configuration on one side of floating lock1200 to be symmetric with the finger/gap configuration on the oppositeside. Floating lock 1200 is responsive to tensional forces, such ascomplementary springs acting on it from two separate directions toprovide resistance longitudinally. Floating lock 1200 effectively moveslongitudinally when acted upon by filter key 500, and is forced toreturn partially towards its original position after fingers 520 offilter key 500 have traversed through gaps 1220. Upon partialretraction, fingers 520 are aligned behind or underneath fingers 1230 offloating lock 1200. FIG. 8B is a top view of floating lock 1200 showinglaterally extending fingers 1230 a,b and adjacent gaps 1220 between thefingers.

FIG. 8C is a cross-sectional view of floating lock 1200, depicting drivekey 1210 a, which is located at one end of floating lock 1200 onlongitudinal or side panel 1240. Drive key 1210 a is opposite a similardrive key 1210 b (not shown), which is located on the oppositelongitudinal panel of floating lock 1200. Both drive keys are designedto have an angled face for slidably interacting with wings 560 a,b ofboss 550 on filter key 500. Each drive key is preferably integrallyfabricated with floating lock 1200; however, the drive keys may befabricated separately and attached to the longitudinal panels offloating lock 1200 by attachment means known in the art. As shown inFIG. 8C, below drive key 1210 a is a position key or physical stop 1250,preferably formed with the supporting lateral wall 1260 of floating lock1200. As shown in FIG. 8B, position key 1250 is situated between drivekeys 1210 a,b. Position key 1250 may be integrally formed with lateralwall 1260, or may be separately attached thereto by any acceptable meansin the prior art, such as bonding, welding, gluing, press fitting, andthe like. Position key 1250 acts as a physical stop to ensure againstover travel of floating lock 1200. Position key 1250 is situated belowdrive keys 1210 a,b by a distance designed to accommodate the insertionof boss 550 of filter key 500. Upon insertion of filter key 500 intofloating lock 1200, boss 550 traverses through gap 1270 in floating lock1200 formed by the space between drive keys 1210 a,b. Wings 560 a,b ofboss 550 extend outward relative to the width of boss 550, traversingbetween lateral wall 1260 and drive keys 1210 a,b. In this manner, wings560 a,b retain floating lock 1200 from retracting back to its originalposition while boss 550 is being inserted. At all times, floating lock1200 is under the retraction force of resilient members, such as tandemsprings, or the like, tending to keep floating lock 1200 in its originalposition, which is preferably a centered position. During insertion offilter key 500, wings 560 a,b interact with drive keys 1210 a,b to shiftfloating lock 1200 longitudinally off-center while under the resilientretraction forces. Upon full insertion, when boss 550 reaches andcontacts position key 1250, wings 560 a,b are no longer held by drivekeys 1210 a,b because the length of drive keys 1210 a,b is shorter thanthe length of boss 550. At this point in the insertion process, thetensional retraction forces shift floating lock 1200 towards itsoriginal position.

Once wings 560 a,b reach position key 1250, and the user releases theinsertion force initially applied on the filter housing assembly, theextraction forces from shutoff plug springs 1110 dominate. These forcespush the filter housing assembly axially outwards, away from floatinglock 1200. Since wings 560 a,b are no longer bound between drive keys1210 a,b and lateral wall 1260, floating lock 1200 will tend to shiftlongitudinally, partially towards its original position as filter key500 moves slightly axially outwards. At this point, wings 560 a,binteract with edge angles 1280 a,b to push away from the centerposition, shifting filter key 500, and combining or contacting with face1300 a,b to keep the filter housing from retracting. FIG. 8D depicts anexploded view of drive key 1210 a with edge angle 1290 a and face 1300a.

Fingers 520 of filter key 500 are now aligned with fingers 1230 offloating lock 1200 and remain in contact in a vertical plane in theaxial direction, prohibiting extraction of the filter housing assemblyfrom the filter base.

It is envisioned that the preferred embodiment of the present inventionwould be disposed in a refrigerator, most likely within the door. Theoutput of the filter assembly may be selectively coupled to a waterdispenser or an ice dispenser. The water source to the refrigeratorwould be in fluid communication with filter base 100, and prohibitedfrom flowing when filter housing assembly 200 is removed from filterbase 100. Shutoff plugs 14 in stanchions 1101 a,b seal fluid flow untilfilter housing assembly 200 is inserted in filter base 100. Uponinsertion, fluid would flow to the filter housing assembly and filterwater would be returned from the filter housing assembly.

All parts of the filter housing assembly 200 and filter base 100 may bemade using molded plastic parts according to processes known in the art.The filter media may be made from known filter materials such as carbon,activated carbons, malodorous carbon, porous ceramics and the like. Thefilter media, which may be employed in the filter housing of the instantinvention, includes a wide variety of filter media capable of removingone or more harmful contaminants from water entering the filter housingapparatus. Representative of the filter media employable in the filterhousing include those found in U.S. Pat. Nos. 6,872,311, 6,835,311,6,797,167, 6,630,016, 5,331,037, and 5,147,722. In addition, the filtercomposition disclosed in the following Published Applications may beemployed as the filter media: US 2005/0051487 and US 2005/0011827.

The filter assembly is preferably mounted on a surface in proximity to asource of water. The mounting means are also preferably in closeproximity to the use of the filtered water produced by the filterhousing apparatus.

While the present invention has been particularly described, inconjunction with a specific preferred embodiment, it is evident thatmany alternatives, modifications and variations will be apparent tothose skilled in the art in light of the foregoing description. It istherefore contemplated that the appended claims will embrace any suchalternatives, modifications and variations as falling within the truescope and spirit of the present invention.

The invention claimed is:
 1. A filter cartridge comprising: a housinghaving a body, a top portion for forming a fluid-tight seal with thebody, and an axis extending in an axial direction along said housing,the housing top portion including: an ingress port; an egress port; anda filter key located on or connected to the housing for matingattachment to a filter base, the filter key axially disposed on saidhousing top portion between said ingress and egress ports and includingan extended finger having a bottom surface being at least partiallyexposed, the extended finger bottom surface including adownwardly-extending mating portion angled with respect to the housingaxis.
 2. The filter cartridge of claim 1, wherein said filter keyextended finger extends from a base portion of said filter key and saidextended finger bottom surface is at least partially exposed to thehousing top portion or a top surface of said filter key base portion. 3.The filter cartridge of claim 1, wherein said extended finger bottomsurface is formed to releasably couple to said filter base during matingattachment.
 4. The filter cartridge of claim 3, wherein said extendedfinger bottom surface is shaped to be received by a slidable lock insaid filter base during mating attachment.
 5. The filter cartridge ofclaim 1, wherein said extended finger bottom surface mating portioncomprises on one side a substantially planar surface angled with respectto the housing axis.
 6. The filter cartridge of claim 1, wherein saidextended finger bottom surface mating portion comprises on one side asubstantially non-planar surface angled with respect to the housingaxis.
 7. The filter cartridge of claim 6, wherein said mating portionsubstantially non-planar surface comprises an at least partially convexsurface.
 8. The filter cartridge of claim 1, wherein the filter keyextended finger includes a diamond-shaped cross-section in a planeparallel to longitudinal sides of the filter key.
 9. The filtercartridge of claim 1, wherein the filter key is fixably or removablyattached to said housing top portion.
 10. The filter cartridge of claim9, wherein the filter key is integral with the housing top portion, orattached to the filter housing top portion by snap fit, friction fit,welding, or bonding.
 11. The filter cartridge of claim 1, wherein theextended finger is integrally formed with the filter key.
 12. The filtercartridge of claim 2, wherein said housing includes a first attachmentstructure for receiving the filter key, and wherein said filter key baseportion includes a second attachment structure for attaching said filterkey to said first attachment structure on said housing.
 13. The filtercartridge of claim 12, wherein said first attachment structure includesan elongated protrusion extending from said housing, and said secondattachment structure includes a groove complementary to said elongatedprotrusion for insertably securing said filter key to said housing byslidably mating said elongated protrusion of said housing within saidgroove.
 14. The filter cartridge of claim 1, wherein said ingress portand said egress port are off axial center of said housing.
 15. Thefilter cartridge of claim 1, further including at least onestrengthening rib on said housing body.
 16. The filter cartridge ofclaim 15, wherein said at least one strengthening rib protrudes radiallyfrom said housing body and extends longitudinally intermediate betweentop and bottom portions of said housing.
 17. A filter cartridgecomprising: a housing having a body, a top portion for forming afluid-tight seal with the body, and an axis extending in an axialdirection along said housing, the housing top portion including: aningress port; an egress port; and a filter key located on or connectedto the housing for mating attachment to a filter base, the filter keyaxially disposed on said housing top portion between said ingress andegress ports and comprising an extended finger including on one side acontacting portion forming a first angle in a first direction withrespect to the housing axis, and a bottom surface being at leastpartially exposed, the extended finger bottom surface including adownwardly-extending mating portion angled with respect to the housingaxis.
 18. The filter cartridge of claim 17, wherein said filter keyextended finger extends from a base portion of said filter key and saidextended finger bottom surface is at least partially exposed to thehousing top portion or a top surface of said filter key base portion.19. The filter cartridge of claim 17, wherein said filter key extendedfinger bottom surface is formed to releasably couple to the filter baseduring mating attachment.
 20. The filter cartridge of claim 19, whereinsaid extended finger bottom surface is shaped to be received by aslidable lock in said filter base during mating attachment.
 21. Thefilter cartridge of claim 17, wherein said filter key extended fingercontacting portion comprises a substantially planar surface, and furtherincluding an adjacent side forming a second angle in the first directionwith respect to the housing axis, such that the first angle and thesecond angle are not equal.
 22. The filter cartridge of claim 17,wherein said filter key extended finger contacting portion comprises asubstantially non-planar surface, and further including an adjacent sideforming a second angle in the first direction with respect to thehousing axis, such that the first angle and the second angle are notequal.
 23. The filter cartridge of claim 17, wherein the filter keyextended finger includes a diamond-shaped cross-section in a planeparallel to longitudinal sides of the filter key.
 24. The filtercartridge of claim 17, wherein the filter key is fixably or removablyattached to said housing top portion.
 25. The filter cartridge of claim24, wherein the filter key is integral with the housing top portion, orattached to the filter housing top portion by snap fit, friction fit,welding, or bonding.
 26. The filter cartridge of claim 17, wherein theextended finger is integrally formed with the filter key.
 27. The filtercartridge of claim 18, wherein the housing includes a first attachmentstructure for receiving the filter key, and wherein said filter key baseportion includes a second attachment structure for attaching said filterkey to said first attachment structure on said housing.
 28. The filtercartridge of claim 27, wherein said first attachment structure includesan elongated protrusion extending from said housing, and said secondattachment structure includes a groove complementary to said elongatedprotrusion for insertably securing said filter key to said housing byslidably mating said elongated protrusion of said housing within saidgroove.
 29. The filter cartridge of claim 17, wherein said ingress portand said egress port are off axial center of said housing.
 30. Thefilter cartridge of claim 17, further including at least onestrengthening rib on said housing body.
 31. The filter cartridge ofclaim 30, wherein said at least one strengthening rib protrudes radiallyfrom said housing body and extends longitudinally intermediate betweentop and bottom portions of said housing.